Content streaming, such as the streaming of audio, video, and/or text is becoming increasingly popular. The term “streaming” is typically used to indicate that the data representing the media is provided over a network to a client computer on an as-needed basis rather than being pre-delivered in its entirety before playback. Thus, the client computer renders streaming content as it is received from a network server, rather than waiting for an entire “file” to be delivered.
The widespread availability of streaming multimedia content enables a variety of informational content that was not previously available over the Internet or other computer networks. Live content is one significant example of such content. Using streaming multimedia, audio, video, or audio/visual coverage of noteworthy events can be broadcast over the Internet as the events unfold. Similarly, television and radio stations can transmit their live content over the Internet.
The Session Description Protocol (SDP), Network Working Group Request for Comments (RFC) 2327, April 1998, is a text-based format used to describe properties of a multimedia presentation, referred to as a “session”, and properties of one or more media streams contained within the presentation. SDP has been developed as an application level protocol intended for describing multimedia sessions for the purposes of session announcement, session invitation, and other forms of multimedia session initiation. SDP can be used in accordance with other protocols, such as the Real-Time Streaming Protocol (RTSP) or the HyperText Transfer Protocol (HTTP), to describe and/or negotiate properties of a multimedia session used for delivery of streaming data.
SDP, however, is limited in the properties of the multimedia presentation that can be described. One solution to such limitations is to embed a different file header, such as an ASF (Advanced Streaming Format or Advanced Systems Format) file header, within an SDP message. Such a solution is described, for example, in U.S. Patent Application No. 2003/0236912, entitled “System and Method for Embedding a Streaming Media Format Header Within a Session Description Message”. However, embedding such a file header can create problems, such as requiring the recipient of such an SDP message to be able to parse and understand the different file header, and increasing the size of the SDP message that includes the different file header. Thus, it would be beneficial to have a way to overcome these limitations of SDP without requiring recipients to be able to parse and understand an embedded different file header (such as ASF).